Blood in semen

The short version: the evidence retrieved does not answer the question you asked. It is a collection of case reports and small studies on post-biopsy bleeding and rare melanoma, not a systematic evaluation of hematospermia in the general population.

The evidence you provided contains three items. One is a 2000 case report of a 33-year-old HIV-positive man whose persistent hematospermia turned out to be metastatic melanoma [1]. That is a single patient, not a population study. Another is a 1994 study on PSA and digital rectal exam for prostate cancer detection, which does not mention hematospermia at all [2]. The third is a 2017 study on prostatic calculi predicting hematospermia after prostate biopsy, which is about a procedure, not spontaneous hematospermia [3]. None of these test the hypothesis that hematospermia is usually linked to identifiable causes and that evaluation should be guided by age and risk factors.

The gap itself matters. No study here compares outcomes for patients who received imaging or biopsy against those who did not. No study tracks how often hematospermia resolves on its own versus how often it signals cancer. The evidence base for the standard clinical approach—reassurance for young men without risk factors, imaging for older men—is not in these records. The burden of proof for any intervention, including a biopsy or an MRI, has not been met by what is shown here.

My call: the evidence retrieved does not support or refute the hypothesis. Confidence: not clear. The question remains unanswered by the studies provided.